Allow Modifiers For Statically Linked Libraries

[deg4uss3r]

I was updating some old code that used the metadeps crate and ran into an issue where I needed to add the +whole-archive modifier to my statically linked C libraries to build and test.

Once I moved to system-deps I noticed that feature wasn't supported, so I had to remove this dependency in favor of modifying the linker outputs manually in my build.rs. It would be nice if this was supported 😄

I have started a WIP PR in #117, if this is not something you would like let me know in the ticket.

⚠ Warning that PR is definitely a work in progress still as I have things building/working but no documentation or code review has been done yet, feel free to let me know your initial thoughts though!